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Expert in Gardner talk: Invasive beetles a threat in North Central Massachusetts

By Michael Hartwell, mhartwell@sentinelandenterprise.com

Updated:
11/27/2012 06:32:26 AM EST

GARDNER -- Massachusetts forests are under assault from two species of invasive beetles, and the state needs help from residents to spot the invaders.

Ecologist Samantha Stelmack, a forest-pest outreach and survey coordinator for the Massachusetts Department of Agricultural Resources, said at a free public lecture at Mount Wachusett Community College on Monday that Asian long-horned beetles and emerald ash borers present a threat to the environment and the economy.

Asian long-horned beetles burrow inside hardwood trees, like maple, birch, willow and elm, and destroy them from the inside. Emerald ash borers only target ash trees, which are needed to make such objects as baseball bats, hammer handles and floor boards.

"If we lose the ash trees, we'll lose those products," Stelmack said.

Both types of beetles are considered invasive and can dominate the local ecosystem if left alone.

Worcester has had Asian long-horned beetle infestations for the past 12 to 15 years, according to Stelmack. They are believed to have come to the United States from infested wooden shipping pallets. They were not recognized in Massachusetts until 2008, when a woman spotted one at her home, found its image on Google and read a request to contact the state if spotted.

Signs of infection in a tree include perfectly round exit holes three-eighths of an inch wide and bark divots a half-inch wide where eggs are laid. Fresh sites will appear bright and may ooze sap.

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Infected trees have to be cut down to stop the Asian long-horned beetle from spreading farther, and so far nearly 32,000 trees have been woodchipped in Worcester alone. The city is still considered infected.

"This is an everyday battle," Stelmack said.

In contrast, the same beetle was caught early in Boston, and only six trees have been destroyed there. It is not considered an active area.

"They are big, lazy bugs, and that's a good thing," Stelmack said, adding that Asian long-horned beetles tend to stay in the same tree once they dig in.

The emerald ash borer, on the other hand, can fly 3 miles in a day and has spread relatively quickly from its initial discovery in Michigan in 2002. Massachusetts is the 18th state affected, and the beetles may have been in the United States since the 1990s.

The holes from an emerald ash borer are much smaller than those of an Asian long-horned beetle and include a D-shaped hole 3 to 4 in diameter. The top third of the ash tree may also die and fail to produce leaves if infected.

The state hung more than 700 sticky, tri-cornered purple traps to detect emerald ash borers this year. Stelmack said the insects are attracted to the color purple, and the traps are to detect the beetles, not eradicate them.

There are different ways to deal with emerald ash borers, including treating the ground with chemicals, cutting down the trees, or stripping a thick ring of bark to prevent the larvae from feeding on the soft outer flesh of the tree.

Stelmack said people who see bugs they think are invasive should take a photo before squishing them, and send the picture to www.mass.gov/agr. She said they get a lot of photos of harmless look-alike bugs sent in, but would rather sort through those then miss a positive sighting.

Linda Patterson, president of Mount Wachusett Community College's Green Society, the sustainability club that invited Stelmack to speak, said they appreciate the work of the Massachusetts Department of Agricultural Resources. She hopes the information will get more people to spot the bugs.

After the talk, Stelmack took a group of nearly a dozen students into the woods to look for signs of invasive beetles. None was found.

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